This application claims benefit of priority from application number 0106300.7 filed Mar. 14, 2001 in Great Britain.
The present invention relates to melt spun yarns having a highly lustrous xe2x80x9cmetallicxe2x80x9d appearance, and to fabrics and garments incorporating such yarns. The present invention also relates to methods of manufacture of such melt spun yarns and fabrics.
Filaments and yarns of metals such as silver and gold have been known and valued for their appearance since antiquity, and real gold or silver thread is still used in garments. More recently, copper thread has been incorporated into, for example, men""s jackets, for perceived health benefits.
Fabrics of woven metal filaments and yarns have also been used to make filter elements, and as conductive cloths to confer electromagnetic shielding properties.
It is also known to use metallised polymer filaments to provide the appearance of a metallic yarn, for example, LUREX(copyright) yarns. Such yarns are typically manufactured by bonding a thin layer of aluminium on to a plastic film, and then cutting the film into very fine strips to make a thread. By incorporating appropriate colours, the yarn can be given the appearance of silver, gold, etc. However, such yarns are relatively coarse and scratchy, and are limited in use to a surface effect. They would be extremely uncomfortable worn next to the skin. Furthermore, the production process is expensive.
It would be highly desirable to produce a yarn of bright metallic appearance suitable for use in textile applications, especially for apparel, and having the feel and other properties of a soft, conventional textile yarn. It would be especially desirable if the yarn could be produced on existing yarn manufacturing equipment at little additional cost relative to conventional yarns.
Since such a yarn is likely to be used as a highlight in the fabric, it is also desirable that the metallic colour should be an inherent property of the as-spun yarn rather than a result of subsequent coating or dyeing of the yarn. This would help to ensure that the metallic-lustre yarn does not stain the other yarns present in the fabric, and also makes it possible for the yarn with metallic lustre not to be affected by the dyeing process used for the remainder of the fabric.
In order to obtain a metallic effect yarn which is visibly distinct from the rest of the fabric, it is desirable that the yarn be coloured before processing into fabric. While it is theoretically possible to dye yarns by conventional means, so-called xe2x80x9cpackage dye yarnsxe2x80x9d, this process is normally restricted to textured yarns which have a structure open enough to permit flow of the dye liquor through the bobbin. Dyeing of the much denser packages obtained with flat yarns is technically difficult, and also expensive, especially at low decitex.
These problems can be solved by the incorporation of pigments and/or dyestuffs into a molten polymer, followed by melt-spinning the polymer into a yarn. Processes of this kind are described in U.S. Pat. Nos. 5,164,261 and 5,391,703. The colourant may be added as a masterbatch, by blending of polymer granules, or by direct injection of the colourant-carrying liquid into an extruder as described in PCT patent document number WO99/14407.
The yarns so produced find particular use as carpet yarns, which are typically of about 1400 decitex with individual filaments about 7 to 20 decitex, and so are much coarser than apparel yarns, which run from about 5 to 300 decitex with individual filaments typically from below 1.0 to around 6 decitex.
It is also known that nylon yarns, which are normally strongly dyed by anionic dyestuffs, can be rendered resistant to such dyestuffs by the incorporation of sulfonate groups within the polymer, as described in U.S. Pat. No. 5,164,261. Such yarns are often referred to as base-dye, cationic-dye, or simply cat-dye yarns, because the chemical group that is responsible for anionic dye resistance also confers cationic dyeable properties on the yarn. Cationic dyes are rarely used in apparel yarns however, and it is the anionic-dye resistance which is of especial interest for the present invention.
It has been found by the present inventors that textile yarns having the metallic colour and lustre and other desirable properties described above can be made by incorporating a pigment into a molten polymer, followed by melt-spinning to give a yarn of a selected cross-section. The yarns are of soft hand and are comfortable to wear as a garment. It has further been found that the metallic effect is yet further enhanced when the metallic yarn is combined in a fabric with dark coloured companion yarn, especially a black yarn, which serves to emphasise the metallic highlights.
Further enhancement of the metallic effect is achieved by selecting companion yarns of higher anionic dye affinity, especially polyamide yarns with Amine End Group (AEG) levels higher than 60 equivalents per 106 g. The anionic dye then tends to be retained on the companion yarn, and anionic staining of the melt coloured yarn is minimised.
In other words, colour differentiation is maximised and cross-staining minimised by using a polymer for the xe2x80x98metallic yarnxe2x80x99 which is anionic-dye resistant, while that of the companion yarn is specifically attractive to anionic dyes. The use of high affinity companion yarns also enables the use of high pH dyeing techniques to increase the stain blocking effect.
Specifically, the present invention provides a profiled polyamide yarn having a yarn weight of from about 5 to about 300 dtex, a filament weight of from about 0.5 to about 7 dtex, and a non-circular profiled filament cross-section, wherein the polyamide comprises from about 0.01 to about 3% of a non-white pigment melt-dispersed therein.